The field of the present invention relates to mechanical contacts and support for printed circuit board (PCB) mountable power modules such as rectifiers, MOSFETs and IGBTs. More specifically, the present invention relates to a system and method of supporting a plurality of mechanical joints through a common mechanical support, i.e., a support which clamps the module to its thermal interface and clamps the PCB to the module.
Current PCB mountable power modules often require two separate points of mechanical contact or support. The first of these two mechanical joints involves a thermal interface of the module to secure a base plate to a heat sink or cold plate. The second of these two mechanical joints involves a solder joint of module terminals to a printed circuit board (PCB) and support of the board.
Typically the thermal interface is addressed by the use of fasteners and/or washers, which secure the base plate or substrate of a power module/device to a heat sink or cold plate. This fulfills the requirements of the first mechanical joint, but the second mechanical joint, which involves the support of the PCB, is left to the solder joint. Through applications of environmental stress like thermal stresses, where there may be a temperature mismatch of materials, or vibrational stresses, there can be enough resulting mechanical stress placed on either the solder terminal joint directly or transferred through the solder-terminal joint to the substrate-terminal joint that this electrical connection will fail. Prior approaches for modules that have features for fasteners through the board and into the shell of the module cause the loss of valuable board space by the additional holes and voltage clearance issues introduced by these additional fasteners.
Thus, there is a need for a system and method of assembly for mechanical contacts and support for PCB mounted power modules which provides the support of both mechanical joints through a common mechanical support by clamping the power module to its thermal interface and clamping the PCB to the module.
Further, there is a need for a system and method of mounting power modules on a PCB which minimizes the use of PCB space in the support of such power modules.
In addition, there is a need for a system and method of installation of mounting power modules on a PCB which uses a simplified design to reduce assembly time.